Encrypted Extensions: Change extensions length check

Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
This commit is contained in:
XiaokangQian 2021-10-13 05:56:18 +00:00
parent 97799ac27b
commit 8db25fffb4

View File

@ -1432,7 +1432,7 @@ static int ssl_tls13_process_encrypted_extensions( mbedtls_ssl_context *ssl )
/* Process the message contents */ /* Process the message contents */
MBEDTLS_SSL_PROC_CHK( MBEDTLS_SSL_PROC_CHK(
ssl_tls13_parse_encrypted_extensions( ssl, buf, ( buf + buf_len ) ) ); ssl_tls13_parse_encrypted_extensions( ssl, buf, buf + buf_len ) );
mbedtls_ssl_tls1_3_add_hs_msg_to_checksum( mbedtls_ssl_tls1_3_add_hs_msg_to_checksum(
ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSION, buf, buf_len ); ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSION, buf, buf_len );
@ -1458,14 +1458,17 @@ static int ssl_tls13_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
int ret = 0; int ret = 0;
size_t extensions_len; size_t extensions_len;
const unsigned char *p = buf; const unsigned char *p = buf;
const unsigned char *extensions_end;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 ); MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 );
extensions_len = MBEDTLS_GET_UINT16_BE( p, 0 ); extensions_len = MBEDTLS_GET_UINT16_BE( p, 0 );
p += 2; p += 2;
MBEDTLS_SSL_DEBUG_BUF( 3, "encrypted extensions", p, extensions_len ); MBEDTLS_SSL_DEBUG_BUF( 3, "encrypted extensions", p, extensions_len );
extensions_end = p + extensions_len;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, extensions_len );
while( p < end ) while( p < extensions_end )
{ {
unsigned int extension_type; unsigned int extension_type;
size_t extension_data_len; size_t extension_data_len;
@ -1476,12 +1479,12 @@ static int ssl_tls13_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
* opaque extension_data<0..2^16-1>; * opaque extension_data<0..2^16-1>;
* } Extension; * } Extension;
*/ */
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 4 ); MBEDTLS_SSL_CHK_BUF_READ_PTR( p, extensions_end, 4 );
extension_type = MBEDTLS_GET_UINT16_BE( p, 0 ); extension_type = MBEDTLS_GET_UINT16_BE( p, 0 );
extension_data_len = MBEDTLS_GET_UINT16_BE( p, 2 ); extension_data_len = MBEDTLS_GET_UINT16_BE( p, 2 );
p += 4; p += 4;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, extension_data_len ); MBEDTLS_SSL_CHK_BUF_READ_PTR( p, extensions_end, extension_data_len );
/* The client MUST check EncryptedExtensions for the /* The client MUST check EncryptedExtensions for the
* presence of any forbidden extensions and if any are found MUST abort * presence of any forbidden extensions and if any are found MUST abort
@ -1501,18 +1504,17 @@ static int ssl_tls13_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT, \ MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT, \
MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION ); MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION );
return ( MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION ); return ( MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION );
break;
} }
p += extension_data_len; p += extension_data_len;
} }
/* Check that we consumed all the message. */ /* Check that we consumed all the message. */
if( p != end ) if( p != extensions_end )
{ {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "EncryptedExtension lengths misaligned" ) ); MBEDTLS_SSL_DEBUG_MSG( 1, ( "EncryptedExtension lengths misaligned" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, \ MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, \
MBEDTLS_ERR_SSL_DECODE_ERROR ); MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
return( MBEDTLS_ERR_SSL_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_DECODE_ERROR );
} }